Calculation of geothermal gradient and hot flow values indicates that the temperature field of Beibuwan Basin is inhomogeneous. Geothermal anomalies are in relation with burial depth of bed rocks, but they are mainly caused by hydrothermal fluid activities. Oil (gas)-bearing wells or oil(gas)fields are usually associated with higher thermal gradient and hot flow values. The anomalous pressure produced from compaction of argillaceous rocks andgeneration of hydrocarbon promotes hydrothermal fluid to burst episodically along syngenetic faults. Heat entrained by hydrothermal fluid continues to conduct and convect right up to the surface where higher hot flow anomaly occures. Hydrothermal fluid activities not only make temperature field inhomogeneous, but also affect the maturation of source rocks. Vitrinite reflectance values in range of oil-generation windows are higher than the values they should be.
Geological Science and Technology Information
geotermal gradient, hot flow active, hydrothermal fluid, Beibuwan Basin